Film contact system



Oct. 20, 1931. TT 1,828,364

FILM CONTACT SYSTEM Filed Jan. 18, 1928 2 Sheets-Sheet l Attorney.

7?: Jlr Pressure Tan/i.

um'rao STATES; PATENT OFFICE- MI E. GABBU'I'T, OF HOLLYWOOD, OALH'OBNIA,ASSIGNOB TO PARAMOUNT PUBLIZ (DBPOBLTION, A CORPORATION 01 NEW YORK v mOONTAG'I. SYSTEM Application fled January 18,1898. Serial No. 847,588.

This invention has to do with printers for motion picture film and thelike, and is particularly concerned with improvements in the system ofprinting by contact.

With film printing systems heretofore in use, a substantial loss ofdefinition has always been introduced in printing motion picture film.This effect is apt to vary in magnitude along the film, resulting inirregularity and a frequent fading of detail. And particularl inprintingla positive, for instance, of a dar scene, in w ic case thenegative is very light, the picture often fades to such an extent that Ithe obtainingof a suitable print is entirely .ll im ssible.

'Pliis loss of definition is due primarily to the difliculty ofmaintaining rfect contact and re 'strationof the two lms. Various meansave been devised to maintain contact and also to maintain registration,but heretofore these ends have not been simultaneously reached in asatisfactory manner.

M invention provides ameans of main- The particular elements of thisembodiment.

are not to be construed, however, as being limitative upon theinvention, but merely as being illustrative of suitable means topracticethe system.

, In the drawings:

Fig. 1 shows a developed and a raw film being pressed in contact againsttheir registering and supporting means in accordance with the invention;1

Fig. 2, is an enlarged view showing the films positioned upon theirregistering and su orting means;

. 1g. 3 1s a side elevation of the aperture taimng perfect contact andregister of the.

Fig. 4 is a view in front elevation showing the aperture gate mountedupon the frame of the printer;

Fig. 5 is a section on line 4-4 of Fig. 4,

Fig. 6 is a view similar to Fig. 5, but with the aperture gate moved tothe ino erative position, indicated in dotted lines in ig. 1;

F1g. 7 is a diagrammatic drawing of the an pressure stem and. electriccontrols.

For simplicity of explanation, it will be heremafter assumed that apositive is to be printed from a negative, it being understood that anegative is printed from a positive in exactl the same manner. 1

Wit particular reference to Fig. 1, the negative film 10 and positivefilm 11 are supported face to'face in a curved plane upon suitableregisterin means, as upon the sprocket wheel 12. e films are illuminatedby the printing light L which transmits li ht 7o throng apertures 13 and14 in the cylin ric shield 15. Sprocket wheel 12 is driven in anconvenient manner, and is provided wit teeth 16 which fit into the filmperforations, thus registering as well as movlng the films. These teethare carefully machmed to fit snugly into the perforations, and supportthe films as shown in Fig. 2. Backing up the films opposite aperture 14is the gate 20. Gate 20 has aconcave face 21 whose curvature conforms tothat of sprocket wheel 12 and is carried upon a swinging arm 22rotatably mounted upon the stud 23 projecting from the printer frame 24.Gate 20 is provided with an air assa having an outlet in itsface 21 oppoite t e aperture '14. In the to shown in the drawmgs, this is acoompished by providing in face 21 an air outlet aperture or slot 25transversely to the films and directly opposite the light aperture 14.Slot 25 communicates by means of drill holes 26 to the air tube 27.

When the printer is not in operation, the gate 20 is swung to itsinoperative position, indicated in dotted line in Fig. 1. For thepurpose of providing a means of cutting of! the air sufpply when thegate is in this position, the o lowing arrangement is provided. Airinlet tube 28 is connected to the air passage 29 extendin throughframe24 and oenmo trally and longitudinally through stud 23. A drillhole 30 extends radially from the surface of the stud 23 to the centralair passage 29, as shown in Figs. 4 and 5, and in register with the hole30 when the arm is in its operative position, that of. Fig. 5, is acorresponding hole 31 extending radially through the hub 32 of arm 22.Air tube 27 is then connected to the outlet of hole 31, thus completingan air passage from air tube 28 to the slot 25 in the face 21 of thegate. When the aperture gate 20 isswung to its inoperative position, asindicated in dotted line in Fig. 1, the holes 30 and 31 in the stud andhub respectively move out of register, as in Fig. 6, and the air supplyis cut off.

The air pressure and electrical system are shown in diagram in Fig. 7.Air under pressure is received through pipe 40 and is reduced toapproximately one and one-half pounds by the pressure regulator 41. Oneand one-half pounds has been found by experiment to be suitable for thespecific apparatus herein sh own, but other pressures will of course berequired for variational apparatus. Pipe 42 conducts the air to astorage tank 43. A mercury U-tube 44 is connected to tank 43 for thepurpose of indicating the pressure of the air in the system.Communicating with tank 43 is a downwardly extending pipe 45, andsurrounding this pipe is an open water tank 46. The height of the waterin the tank 46 above the bottom of the pipe is so proportioned that,with a normal air pressure of one and one-half pounds in the tank 43gforinstance, the water will extend upwardlyinto the pipe 45 to a certainheight and the air cannot escape; but if the air pressure exceeds apredetermined amount, the air will force the water out of pipe 45 andwill escape upwardly through the water in the tank. A water outlet pipe47 is provided in the side of tank 46. the height of this pipe beingadjusted to maintain iust the height of water necessary to effect theair escape at the predetermined maximum allowable pressure. This airescape safety device precludes any possibility of injury to the film incase of an undue increase in pressure.

As a secondary precaution, means is provided for automatically cuttingofi the supply of electricity to the printer motors and thus stoppingthe motion of the films whenever the pressure either rises or fallsbeyond predetermined limits. Communicating with tank 43 is pipe 50having at its end the open mercury U tube 51. In series with solenoid52, which holds circuitbreaker 53 closed, are two platinum contacts orelectrodes 54 and 55, dipping into the surfaces of. the mercury 56 inthe arms of the U-tube 51. When the 7 pressure in the system changes,the mercury change is suflicient, the mercury in the latter arm willdescend until contact between the electrode and the mercury is broken.The solenoid 52 is thus de-energized, the circuit breaker 53 opens andthe printer motors, such as motor M, stop. A stationary electricalcontact 57 and a corresponding contact 58 situated on the circuitbreaker 53 are provided in an auxiliary circuit 59 which includesbattery B and bell 60. When the circuit breaker 53 opens the contacts 57and 58 are closed, ringing the bell 60 which notifies tliife operatorimmediately that his power is o A single air pressure system andelectrical controls such as has just been described may be connected toa number of printing machines. A pipe leading from storage tank 43communicates with the air tubes 28 of the various printers. An aircleaner 71 is provided at a convenient point in each air tube so that nodirt will be blown against the film. This air cleaner may convenientlyconsist of a silk bag or other fine mesh fabric through which the airmust pass on its way to the gate.

It is recognized that air pressure has been previously used to cause abetter contact of the films, but heretofore this has always been appliedto the concave surface of the curved plane to which the films conform inpassing over their registering and driving sprocket. The effect of thusapplying an air pressure is to move the films slightly away from a tightfit upon the sprocket teeth, and thus to lose the effect of perfectregistration which may only be obtained by causing the films to fittightly against the sprocket wheel with the sprocket teeth fittingsnugly into the perforations. Another disadvantage of applying airpressure in this manner is that the films are often scratched by beingrubbed against the ate.

y invention, in providing means of applying air pressure to the convexinstead of the concave surface of the films, obviates these difficultiesand permits the obtainment of greatly improved prints. As indicated inFig. 2, the films are pressed into perfect contact and are forced uponthe sprocket teeth, thus insuring a snug fit and the best possibleregistration. The natural rigidity of the films prevents themfrombuckling between the teeth of the sprocket wheel from the maximum airpressure that is used. Before sufficient pressure to cause buckling orto injure the film in any way is reached, the water safety valve allowsair to escape and the electric drive is opened, stoppin the machine, aswas previously explaine Printing is thus accomplished under the bestpossible conditions. The films, which are disposed in a curved planeupon their registering means, are pressed from their convex surface thusforcing them in tight contact 'ing teeth adapted to fit into the filmsfrom their convex surface in such a' snu 1y down in perfect registerupon the teeth of the sprocket wheel. And due tothe safety devices theprinter can only operate when the air pressure is at the proper valuefor best results.

Other arrangements of the various elements of the system will be obviousto those skilled in the. art, and all such wivalent variations arecontemplatedwithin t e scope of-the invention. While I have specified,air

pressure, an suitable fluid substance may be substituted or air, ifdesired. And various forms of aperture gates, sprockets, etc., ma beutilized while practicing the invention. therefore desire to reserve tomyself all such variations and improvements as are included within thefollowing claims: I iii f h h t 1. a system 0 p otograp ic prin ing bythe contact method, a sprocket wheel havrforations of a developed and araw film disposed face to face, the two films being registered and suprted in a curved plane upon the said teet a fluid pressure system, means*for exerting said fluid pressure to an area of the manner that thefilms are held in contact and register a inst the teeth of the' sprocketwheel wit in said area, the pressure being just suflicient to maintaincontact of the films and to seat them snugly upon the sprocket teethwithout causing buck ing of the films between the teeth, means forallowing fluid to escape from the system when the fluid pressure risesabove a predetermined maximum,

.and means for illuminating a portion of the developed film within thearea under pressure so that light will be transmitted through thedeveloped film to print the, raw film.

films are held in contact and. register against the teeth of thesprocket wheel within this area, the premure being just suflicient tomaintain contact of the films and to seat them snugly upon the sprocketteeth without causing buckling of the films between the teeth,

pressure actuated means for automatically 7 cutting off the drive of thesprocket wheel when the pressure departs from a predetermined operatingran'ge, and means for illuminating a portion of the developed filmwithin the area under pressure so that light will be transmitted throughthe developed film to print the raw film.

3. In combination with a system of photographic printinghaving a fluidpressure) system for maintaining contact of a developed and a raw filmand having an electrical circult including a motor for driving filmmovmg mechan1sm,;meax1s actuated byvirtue of 'aredetermined operatingran for cuttin o the drive of said motor. g6 g 4.:In combination with asystem of photographic printing having a fluid pressure pressure eitherrising or falling from e system tube having one of its arms connected tothe 4 pressure system, an electrode dipping into the surface of themercury in each arm, the electrodes being included in the previouslymentioned electrical circuit, the mercury moving out of contact with oneof the electrodes, opening the electrical circuit and stopping themotors when the internal 7 sure within the U tube changes suflicient y.

5. In a system of hotogra hic printing by the contact metho means i andregistering a raw and a develo d film face to face in a curved plane, agate adjacent the convex surface of the films, the film gate having anair pressure outlet designed to project air against the convex sur-:

face of the films, forcing. them against the said registering andsupporting means, the said film gate being movable away from the filmsto an inoperative automatically cutting o the air supply to the gatewhen the gate is moved to its inoperative position, and a source ofillumination disposed op to the surface OfrthQ developed film anmaptedto transmit light therethrough to print the raw film.

6., In a system of photographic printing by the contact method, meansfor supporting and registering a raw and a developed film face to facein a curved plane, a film gate adjacent the convex surface of the films,the film gate havingantair pressure outlet designed to project airagainst the convex surface of the films, forcing them against the saidregistering and supporting means, the said film gate being movable awayfrom the films to an inoperative position, means for automaticallyvcutting ofi the flow of air through the gate when the gate is moved toits inoperative position,'and. a source of illumination disposedopposite the surface of the developed film and adapted to transmittherethrough to print the raw film.

7. In a. continuous printer, the combination of a continuously rotatingsprocketwheel light or supporing Eosition, means for fit filmperforations and to register and sup- 4 I neaaau port films in a curvsiformation out of contact with other portions of the sprocket wheel, afilm ate having a concave inner surface adap to lie closely to theconvex outer surface of films supported on the sprocket wheel, means inthe gate for transmitting fluid under ressure to an area of said convexfilm su ace, means to supply said pressure fluid at the gate under apressure sufiicient to hold the convex film surface away from the gateand to hold the films in mutual contact and tightly upon the sprocketteeth, but insufiicient to cause film buckling between successivesprocket teeth, 15 and means to illuminate a film within the area towhich fluid pressure is ap lied.

In witness that claim the oregoing I have hereunto subscribed my namethis 5th day of January, 1928.

20 FRANK E. GARBUTT.

